/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

package org.apache.iotdb.db.mpp.plan.analyze;

import org.apache.iotdb.db.conf.IoTDBDescriptor;
import org.apache.iotdb.db.exception.sql.PathNumOverLimitException;

/**
 * apply MaxQueryDeduplicatedPathNum and SLIMIT & SOFFSET
 */
public class ColumnPaginationController {

    private int curLimit =
            IoTDBDescriptor.getInstance().getConfig().getMaxQueryDeduplicatedPathNum() + 1;
    private int curOffset;

    // records the path number that the SchemaProcessor totally returned
    private int consumed = 0;

    // for ALIGN BY DEVICE / DISABLE ALIGN / GROUP BY LEVEL / LAST, controller does is disabled
    private final boolean isDisabled;

    public ColumnPaginationController(int seriesLimit, int seriesOffset, boolean isDisabled) {
        // for series limit, the default value is 0, which means no limit
        this.curLimit = seriesLimit == 0 ? this.curLimit : Math.min(seriesLimit, this.curLimit);
        // series offset for result set. The default value is 0
        this.curOffset = seriesOffset;
        this.isDisabled = isDisabled;
    }

    public boolean hasCurOffset() {
        if (isDisabled) {
            return false;
        }

        return curOffset != 0;
    }

    public boolean hasCurLimit() {
        if (isDisabled) {
            return true;
        }

        return curLimit != 0;
    }

    public void consumeOffset() {
        if (isDisabled) {
            return;
        }

        curOffset--;
    }

    public void consumeLimit() {
        consumed++;
        if (consumed > IoTDBDescriptor.getInstance().getConfig().getMaxQueryDeduplicatedPathNum()) {
            throw new PathNumOverLimitException();
        }

        if (isDisabled) {
            return;
        }
        curLimit--;
    }
}
